During semiconductor processing of semiconductor substrates, such as silicon wafers in a vacuum chamber, it is necessary to place the substrate on a cathode support during processing, such as etching or chemical vapor deposition. The substrates can be held in place with contact rings or fingers around its periphery to hold the substrate firmly in place on the cathode support. However, mechanical parts such as rings or fingers interfere with processing around the edges of the substrate, and they can generate particles in the reaction chamber during raising and lowering of the rings or fingers.
Electrostatic cathode supports or chucks have also been suggested. These chucks or cathode supports are connected to an external HV power source external to the vacuum chamber in order for a dielectric coated conductive film on the chuck to produce an electrostatic charge on the surface of the chuck sufficient to maintain the substrate in place during processing. However, in practice implementation of these chucks present certain difficulties. The cathode or chuck is itself supported on a fixed base, generally of aluminum, which is situated on the bottom wall of the reaction chamber. This base must contain a plurality of openings including a large central opening for a lift mechanism to move the wafer down onto the chuck into its processing position in the chamber and up again after processing is complete, and in addition the base contains openings for an RF power source line, a plurality of water and gas (helium) lines for cooling the base, cathode or chuck and the substrate supported thereon during processing. When it is desired to add a HV line to the chuck, still another opening must be made, which must compete for space in the cathode base.
Further, it has been the practice to insert the HV power line through the base with an extension for the HV cable. When the reaction chamber is disassembled, as during cleaning operations or repairs, care must be taken not to damage the protruding HV line. Since the base is quite heavy, this is no small feat.
When a two part HV connector is used, such as a flange mounted or jam nut mounted receptacle, suitably a standard circular MIL-C-5015 receptacle, the two parts must be connected after the reaction chamber is assembled, necessitating enough room in the bottom of the base to assure that a tight connection is made along with a vacuum seal, again competing for space in the base with other required channels and openings. Further, a portion of the metal receptacle is in the vacuum chamber in a vacuum environment, which can cause arcing during processing, as well as the generation of particles within the chamber,
Thus a HV connector that provides reliable contact between an outside source of HV power and a reactor part, one that does not take up much space in the reaction chamber base, that does not generate particles in the chamber, nor cause arcing during processing, and that can be permanently mounted in the base so that it does not interfere with disassembly or cleaning of the reaction chamber, would be highly desirable.